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1.
ACS Omega ; 9(13): 15015-15029, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38585106

RESUMEN

The effectiveness of a copper(II) complex with a Schiff base derived from 2-amino-4-phenyl-5-methylthiazole and salicylaldehyde (APMS) as a corrosion inhibitor for XC18 steel in an HCl solution was investigated. Experimental findings indicated a slight negative correlation between inhibition efficiencies in 1 M HCl and temperature but a positive correlation with both inhibitor concentration and immersion time, respectively. The weight loss measurement revealed that APMS achieved a maximum inhibition rate of 92.07% at 303 K. A fitting analysis demonstrated that APMS adheres to the Langmuir adsorption isotherm. The electrochemical results revealed an enhanced inhibitive performance of APMS, with the efficiency increasing as concentrations increased, ultimately reaching a peak of 94.47% at 5 × 10-3 mol L-1. Potentiodynamic polarization measurements revealed that APMS acted as a mixed-type inhibitor without affecting the corrosion mechanism. Scanning electron microscopy investigations of the metal surfaces corroborated the presence of an adsorbed organic layer. Advanced theoretical calculations utilizing density functional theory and first-principles density-functional tight-binding were conducted to gain insights into the behavior of APMS on the metal surface. APMS derives its advantages from crucial inter- and intramolecular interactions, resulting in the formation of a resilient adsorption layer, in line with the experimental findings. It is found that the presence of the APMS-based inhibitor exhibits a significant synergistic corrosion inhibition effect. The current study offers a design direction for enhancing the structural characteristics of Schiff base metal complexes, laying the groundwork for multifunctional frameworks to minimize corrosion rates with considerations for real-world use and cost-efficiency. The ability to replace harmful, expensive constituents with sustainable, and cost-effective organic alternatives represents a significant outcome of this study.

2.
Macromol Biosci ; 24(6): e2300540, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38456554

RESUMEN

The scaffold is a porous three-dimensional (3D) material that supports cell growth and tissue regeneration. Such 3D structures should be generated with simple techniques and nontoxic ingredients to mimic bio-environment and facilitate tissue regeneration. In this work, simple but powerful techniques are demonstrated for the fabrication of lamellar and honeycomb-mimic scaffolds with poly(L-lactic acid). The honeycomb-mimic scaffolds with tunable pore size ranging from 70 to 160 µm are fabricated by crystal needle-guided thermally induced phase separation in a directional freezing apparatus. The compressive modulus of the honeycomb-mimic scaffold is ≈4 times higher than that of scaffold with randomly oriented pore structure. The fabricated honeycomb-mimic scaffold exhibits a hierarchical structure from nanofibers to micro-/macro-tubular structures. Pre-osteoblast MC3T3-E1 cells cultured on the honeycomb-mimic nanofibrous scaffolds exhibit an enhanced osteoblastic phenotype, with elevated expression levels of osteogenic marker genes, than those on either porous lamellar scaffolds or porous scaffolds with randomly oriented pores. The advanced techniques for the fabrication of the honeycomb-mimic structure may potentially be used for a wide variety of advanced functional materials.


Asunto(s)
Nanofibras , Osteoblastos , Poliésteres , Andamios del Tejido , Andamios del Tejido/química , Nanofibras/química , Ratones , Animales , Osteoblastos/citología , Osteoblastos/metabolismo , Osteoblastos/efectos de los fármacos , Poliésteres/química , Porosidad , Línea Celular , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Ingeniería de Tejidos/métodos , Osteogénesis/efectos de los fármacos
3.
Materials (Basel) ; 17(5)2024 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-38473647

RESUMEN

Growing research activity on layered double hydroxide (LDH)-based materials for novel applications has been increasing; however, promoting LDH layer growth and examining its morphologies without resorting to extreme pressure conditions remains a challenge. In the present study, we enhance LDH growth and morphology examination without extreme pressure conditions. By synthesizing Mg-Al LDH directly on plasma electrolytic oxidation (PEO)-treated Mg alloy surfaces and pores at ambient pressure, the direct synthesis was achieved feasibly without autoclave requirements, employing a suitable chelating agent. Additionally, enhancing corrosion resistance involved incorporating electron donor-acceptor compounds into a protective layer, with 8-Hydroxyquinoline-5-sulfonic acid (HQS) that helps in augmenting Mg alloy corrosion resistance through the combination of LDH ion-exchange ability and the organic layer. DFT simulations were used to explain the mutual interactions in the LDH system and provide a theoretical knowledge of the interfacial process at the molecular level.

4.
Materials (Basel) ; 17(6)2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38541406

RESUMEN

This study explores the combined potential of severe plastic deformation (SPD) via differential speed rolling (DSR) and plasma electrolytic oxidation (PEO) to enhance the material performance of 6061 Al alloys. To this end, DSR was carried out at a roll-speed-ratio of 1:4 to obtain ~75% total thickness reduction and a final microstructure of <1 µm. The rest of the samples were annealed to obtain various grain sizes of ~1, ~25, and ~55 µm. Through DSR, the hardness of the material increased from ~64 to ~102 HV. Different grain sizes altered the plasma behavior which further influence the growth of the coating layer, where the fine grain size produced a compact structure beneficial for corrosion protection. This synergy offers tailored materials ideal for high-performance applications across diverse industries, combining enhanced bulk properties from DSR with optimized surface attributes from PEO.

5.
Environ Res ; 246: 118112, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38184060

RESUMEN

There is growing focus on the crucial task of effectively capturing carbon dioxide (CO2) from the atmosphere to mitigate environmental consequences. Metal-organic frameworks (MOFs) have been used to replace many conventional materials in gas separation, and the incorporation of ionic liquids (ILs) into porous MOFs has shown promise as a new technique for improving CO2 capture and separation. However, the driving force underlying the electronic modulation of MOF nanostructures and the mechanisms behind their high CO2 adsorption remain unclear. This study reports the effect of encapsulating different imidazolium ILs in porous ZIF-8, to clarify the adsorption mechanism of CO2 using density functional theory (DFT)-based approaches. For this purpose, a range of anions, including bis(trifluoromethylsulfonyl)imide [NTf2], methanesulfonate [MeSO3], and acetate [AC], were combined with the 1-ethyl-3-methylimidazolium [EMIM]+ cation. [EMIM]+-based ILs@ZIF-8 composites were computationally investigated to identify suitable materials for CO2 capture. First, the intermolecular and intramolecular interactions between [EMIM]+ and different anions were examined in detail, and their effects on CO2 adsorption were explored. Subsequently, the integration of these ILs into the ZIF-8 solid structure was studied to reveal how their interactions influenced the CO2 adsorption behavior. Our results demonstrate that the incorporation of ILs strongly affects the adsorption capability of CO2, which is highly dependent on the nature of the ILs inside the ZIF-8 framework. DFT simulations further confirmed that the incorporation of ILs into ZIF-8 led to superior CO2 capture compared to isolated ILs and pristine ZIF-8. This improvement was attributed to the mutual interactions between the ILs and ZIF-8, which effectively fine-tuned CO2 adsorption within the composite structure. This understanding may act as a general guide for gaining more insight into the interfacial interactions between ILs and ZIFs structures and how these molecular-level interactions can help predict the selection of ILs for CO2 adsorption and separation, thereby addressing environmental challenges with greater precision and effectiveness.


Asunto(s)
Líquidos Iónicos , Estructuras Metalorgánicas , Dióxido de Carbono/química , Líquidos Iónicos/química , Adsorción , Aniones/química , Metales
6.
Nanomicro Lett ; 15(1): 213, 2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37736827

RESUMEN

Porous organic frameworks (POFs) have become a highly sought-after research domain that offers a promising avenue for developing cutting-edge nanostructured materials, both in their pristine state and when subjected to various chemical and structural modifications. Metal-organic frameworks, covalent organic frameworks, and hydrogen-bonded organic frameworks are examples of these emerging materials that have gained significant attention due to their unique properties, such as high crystallinity, intrinsic porosity, unique structural regularity, diverse functionality, design flexibility, and outstanding stability. This review provides an overview of the state-of-the-art research on base-stable POFs, emphasizing the distinct pros and cons of reticular framework nanoparticles compared to other types of nanocluster materials. Thereafter, the review highlights the unique opportunity to produce multifunctional tailoring nanoparticles to meet specific application requirements. It is recommended that this potential for creating customized nanoparticles should be the driving force behind future synthesis efforts to tap the full potential of this multifaceted material category.

7.
Materials (Basel) ; 16(15)2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37569963

RESUMEN

Metal injection molding (MIM) is a representative near-net-shape manufacturing process that fabricates advanced geometrical components for automobile and device industries. As the mechanical performance of an MIM product is affected by green-part characteristics, this work investigated the green part of pure copper processed with MIM using the injection temperature of ~180 °C and injection pressure of ~5 MPa. A computational analysis based on the Moldflow program was proposed to simulate the effectivity of the process by evaluating the confidence of fill, quality prediction, and pressure drop of three distinctive regions in the green part. The results showed that the ring and edge regions of the green parts showed localized behavior, which was related to processing parameters including the position of the gate. A microstructural observation using scanning electron microscopy and a 3D X-ray revealed that both the surface and body matrix consisted of pores with some agglomeration of micro-pores on the edges and ring part, while any critical defects, such as a crack, were not found. A microhardness analysis showed that the three regions exhibited a reasonable uniformity with a slight difference in one specific part mainly due to the localized pore agglomeration. The simulation results showed a good agreement with the microstructures and microhardness data. Thus, the present results are useful for providing guidelines for the sound condition of MIM-treated pure copper with a complex shape.

8.
Materials (Basel) ; 16(15)2023 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-37570128

RESUMEN

This study explores the application of ultrasonic vibration during plasma electrolytic oxidation (PEO) to enhance the corrosion resistance of magnesium (Mg) alloy. To this end, three different ultrasonic frequencies of 0, 40, and 135 kHz were utilized during PEO. In the presence of ultrasonic waves, the formation of a uniform and dense oxide layer on Mg alloys is facilitated. This is achieved through plasma softening, acoustic streaming, and improved mass transport for successful deposition and continuous reforming of the oxide layer. The oxide layer exhibits superior protective properties against corrosive environments due to the increase in compactness. Increasing ultrasonic frequency from 40 to 135 kHz, however, suppresses the optimum growth of the oxide layer due to the occurrence of super-soft plasma swarms, which results in a low coating thickness. The integration of ultrasonic vibration with PEO presents a promising avenue for practical implementation in industries seeking to enhance the corrosion protection of Mg alloys, manipulating microstructures and composition.

9.
Materials (Basel) ; 16(10)2023 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-37241394

RESUMEN

This investigation studied the effect of reduction sequence during rolling of ferritic stainless steel on texture and anisotropy. A series of thermomechanical processes were performed on the present samples utilizing rolling deformation, with a total height reduction of 83% but with different reduction sequences, 67% + 50% (route A) and 50% + 67% (route B). Microstructural analysis showed that no significant difference was found in terms of the grain morphology between route A and route B. In terms of the texture, as compared to route A, route B developed a sharper texture on all components along the γ-fiber and a considerably higher fraction of boundaries that displayed 38°111 misorientations with respect to the surrounding deformed grains. In consequence, optimal deep drawing properties were achieved, where rm was maximized and Δr was minimized. Moreover, despite the similar morphology between the two processes, the resistance toward ridging was improved in the case of route B. This was explained in relation to the selective growth-controlled recrystallization, which favors the formation of microstructure with homogeneous distribution of the <111>//ND orientation.

10.
Molecules ; 28(8)2023 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-37110779

RESUMEN

The development of corrosion inhibitors with outstanding performance is a never-ending and complex process engaged in by researchers, engineers and practitioners. The computational assessment of organic corrosion inhibitors' performance is a crucial step towards the design of new task-specific materials. Herein, the electronic features, adsorption characteristics and bonding mechanisms of two pyridine oximes, namely 2-pyridylaldoxime (2POH) and 3-pyridylaldoxime (3POH), with the iron surface were investigated using molecular dynamics (MD), and self-consistent-charge density-functional tight-binding (SCC-DFTB) simulations. SCC-DFTB simulations revealed that the 3POH molecule can form covalent bonds with iron atoms in its neutral and protonated states, while the 2POH molecule can only bond with iron through its protonated form, resulting in interaction energies of -2.534, -2.007, -1.897, and -0.007 eV for 3POH, 3POH+, 2POH+, and 2POH, respectively. Projected density of states (PDOSs) analysis of pyridines-Fe(110) interactions indicated that pyridine molecules were chemically adsorbed on the iron surface. Quantum chemical calculations (QCCs) revealed that the energy gap and Hard and Soft Acids and Bases (HSAB) principles were efficient in predicting the bonding trend of the molecules investigated with an iron surface. 3POH had the lowest energy gap of 1.706 eV, followed by 3POH+ (2.806 eV), 2POH+ (3.121 eV), and 2POH (3.431 eV). In the presence of a simulated solution, MD simulation showed that the neutral and protonated forms of molecules exhibited a parallel adsorption mode on an iron surface. The excellent adsorption properties and corrosion inhibition performance of 3POH may be attributed to its low stability compared to 2POH molecules.

11.
Materials (Basel) ; 16(6)2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36984396

RESUMEN

Metal injection molding (MIM) is a quick manufacturing method that produces elaborate and complex items accurately and repeatably. The success of MIM is highly impacted by green part characteristics. This work characterized the green part of steel produced using MIM from feedstock with a powder/binder ratio of 93:7. Several parameters were used, such as dual gates position, injection temperature of ~150 °C, and injection pressure of ~180 MPa. Analysis using Moldflow revealed that the aformentioned parameters were expected to produce a green part with decent value of confidence to fill. However, particular regions exhibited high pressure drop and low-quality prediction, which may lead to the formation of defects. Scanning electron microscopy, as well as three-dimensional examination using X-ray computed tomography, revealed that only small amounts of pores were formed, and critical defects such as crack, surface wrinkle, and binder separation were absent. Hardness analysis revealed that the green part exhibited decent homogeneity. Therefore, the observed results could be useful to establish guidelines for MIM of steel in order to obtain a high quality green part.

12.
Materials (Basel) ; 15(23)2022 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-36500184

RESUMEN

In the present work, we present the superior corrosion inhibition properties of three plant-based products, Fraxinus excelsior (FEAE), Zingiber zerumbet (ZZAE), and Isatis tinctoria (ITAE), that efficiently inhibit the corrosion of mild steel in phosphoric acid. The anti-corrosion and adsorption characteristics were assessed using a combination of experimental and computational approaches. Weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy methods were used to evaluate the inhibitive performance of the inhibitors on the metal surface. Then, both DFT/DFTB calculations and molecular dynamic simulations were further adopted to investigate the interaction between organic inhibitor molecules and the metal surface. The protective layers assembled using the active constituents, such as carbonyl and hydroxyl groups, of the three plant-based products offer high electrochemical stability at high temperatures and robust protection against aggressive acidic solutions. All electrochemical measurements showed that the inhibition performance of extracts increased by increasing their concentration and improved in the following order: FEAE > ZZAE > ITAE. Further, these extracts worked as mixed-type inhibitors to block the anodic and cathodic active sites on the mild steel surface. Multi-level computational approaches revealed that FEAE is the most adsorbed inhibitor owing to its ability to provide electron lone pairs for electrophilic reactions. The experimental and theoretical results showed good agreement. These results indicate the possibility of replacing conventional compounds with natural substituted organic products in the fabrication of hybrid materials with effective anti-corrosion performance.

13.
Materials (Basel) ; 15(20)2022 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-36295137

RESUMEN

The present work dealt with the development of a protective and functional oxide layer via one-step plasma electrolytic oxidation (PEO) on pure titanium by employing highly concentrated aluminate solution in a short processing time. A compositional analysis showed that Al2TiO5 active compound was formed successfully by means of Al2O3 incorporation when TiO2 was spontaneously developed with the aid of plasma swarms. The electrochemical performance showed the protective and functional capabilities of the layer, which was attributed to the respective amounts of Al2O3 and Al2TiO5. Such capabilities were achieved in a short processing time, thus reducing the total production cost.

14.
Front Psychol ; 13: 932777, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35941944

RESUMEN

The COVID-19 pandemic has led to an abrupt transition from face-to-face learning to online learning, which has also affected the mental health of college students. In this study, we examined the relationship between students' adjustment to online learning and their mental health by using the Dual-Continua Model. The model assumes that mental disorder and mental well-being are related yet distinct factors of mental health. For this purpose, 2,933 college students completed an online survey around the beginning of the Fall semester of 2020 (N = 1,724) and the Spring semester of 2021 (N = 1,209). We assessed participants' mental well-being, mental disorders, and academic distress by means of the online survey. In addition, we incorporated grades and log data accumulated in the Learning Management System (LMS) as objective learning indicators of academic achievement and engagement in online learning. Results revealed that two dimensions of mental health (i.e., mental well-being and mental disorder) were independently associated with all objective and subjective online learning indicators. Specifically, languishing (i.e., low levels of mental well-being) was negatively associated with student engagement derived from LMS log data and academic achievement and was positively associated with self-reported academic distress even after we controlled for the effects of mental disorder. In addition, mental disorder was negatively related to student engagement and academic achievement and was positively related to academic distress even after we controlled for the effects of mental well-being. These results remained notable even when we controlled for the effects of sociodemographic variables. Our findings imply that applying the Dual-Continua Model contributes to a better understanding of the relationship between college students' mental health and their adaptation to online learning. We suggest that it is imperative to implement university-wide interventions that promote mental well-being and alleviate psychological symptoms for students' successful adjustment to online learning.

15.
Materials (Basel) ; 15(10)2022 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-35629742

RESUMEN

Steel sheets containing 0.18 wt % C were deformed by differential speed rolling (DSR) up to four passes and compared to the steel sheets processed by equal speed rolling (ESR). Not only microstructure, but also mechanical properties and rolling load, were studied, which enlightens the relationship between microstructure, mechanical properties, and rolling load. Moreover, microstructure and properties resulting from ESR were systematically compared. During the rolling deformation, coarse grains were elongated first parallel to the rolling direction, and ultrafine grains were subsequently formed via continuous dynamic recrystallization. Microstructural analysis revealed that DSR was more effective than ESR in terms of achieving grain refinement and microstructure homogeneity. High-angle grain boundaries surrounding the ultrafine grains contributed to grain boundary strengthening, resulting in a dramatic increase in both hardness and strength after DSR. Although the steel was strengthened by rolling, the rolling load firstly increased and subsequently decreased as the number of passes increased, and lower force was required during DSR than during ESR. These can be explained by considering deformation volume and sticking friction.

16.
J Colloid Interface Sci ; 622: 452-468, 2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-35525147

RESUMEN

It is difficult to comprehensively understand the interfacial mechanism (IM) of the adsorption of corrosion inhibitors (CIs) on metal surfaces solely through experiments and electronic structure parameters of isolated molecules. To better understand the molecular-level IM of CIs, a combination of atomistic simulations and first-principles calculations was used to obtain reliable information on the adsorption nature and intermolecular interactions during the actual interfacial behavior. The IM and property changes of two synthesized heterocyclic sustainable-green CIs, namely 4-{[(5-nitrofuran-2-yl)methylene]amino}-5-propyl-4H-1,2,4-triazole-3-thiol (NFPT and 4-{[(5-nitrofuran-2-yl)methylene]amino}-4H-1,2,4-triazole-3-thiol (NFT), were investigated on the Fe(110) surface using first-principles density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The NFPT was preferentially adsorbed through a parallel configuration with a high interaction energy (-706.12 kJ·mol-1) compared to NFT, owing to stronger chemical bonds via S, N, and O atoms with the Fe surface. Additionally, the adsorbed NFPT film effectively inhibited Fe surface corrosion owing to the small diffusion coefficient of corrosive particles in the presence of NFPT. Subsequently, the anti-corrosion performance of both CIs was validated through electrochemical methods, surface analysis, and adsorption isotherm models. The observations suggest that the combination of modern computational perspectives could efficiently design and select the best CIs before their laboratory synthesis.


Asunto(s)
Compuestos Heterocíclicos , Nitrofuranos , Adsorción , Corrosión , Metales , Compuestos de Sulfhidrilo
17.
BMC Psychol ; 10(1): 88, 2022 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-35379349

RESUMEN

BACKGROUND: As the COVID-19 (Coronavirus disease 2019) pandemic is prolonged, psychological responses to the pandemic have changed, and a new scale to reflect these changes needs to be developed. In this study, we attempt to develop and validate the COVID-19 Impact Scale (CIS) to measure the psychological stress responses of the COVID-19 pandemic, including emotional responses and difficulty with activities of daily living. METHODS: We recruited 2152 participants. Participants completed the CIS, the Fear of COVID-19 Scale (FCV-19S), and other mental health related measures. The factor structure, reliability, and validity of the CIS were analyzed. In addition, the validity of the scale was confirmed by its relationships to the existing measures assessing fear of COVID-19, depression, anxiety, subjective well-being, and suicidal ideation. RESULTS: Using exploratory factor analysis (N1 = 1076), we derived a one-factor structure. In confirmatory factor analysis (N2 = 1076), the one-factor model showed good to excellent fitness. The CIS was positively correlated with depression, anxiety, suicidal ideation, fear of COVID-19 and negatively correlated with subjective well-being. The FCV-19S did not show significant correlations with subjective well-being or suicidal ideation, and FCV-19S's explanatory powers on depression and anxiety were lower than those of the CIS. CONCLUSIONS: These results support that the CIS is a valid assessment of emotional problems and deterioration of the quality of life caused by the COVID-19 pandemic. Finally, the limitations of this study and future research directions are discussed.


Asunto(s)
COVID-19 , Actividades Cotidianas , Humanos , Pandemias , Calidad de Vida , Reproducibilidad de los Resultados
18.
Membranes (Basel) ; 12(3)2022 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-35323744

RESUMEN

The effects of benzalkonium chloride (BKC) contents on the structure, properties, and ultrafiltration performance of chitosan-based nanocomposite membranes containing poly(ethylene glycol) and multi-walled carbon nanotube (chitosan/BKC/PEG/CNT) were examined. The membranes were prepared by a mixing solution method and phase inversion before being characterized with microscopic techniques, tensile tests, thermogravimetric analysis, water contact angle, and porosity measurements. The performance of the nanocomposite membranes in regard to permeability (flux) and permselectivity (rejection) was examined. The results show that the incorporation of BKC produced nanocomposite membranes with smaller pore structures and improved physico-chemical properties, such as an increase in porosity and surface roughness (Ra = 45.15 to 145.35 nm and Rq = 53.69 to 167.44 nm), an enhancement in the elongation at break from 45 to 109%, and an enhancement in the mechanical strength from 31.2 to 45.8 MPa. In contrast, a decrease in the membrane hydrophilicity (water contact angle increased from 56.3 to 82.8°) and a decrease in the average substructure pore size from 32.64 to 10.08 nm were observed. The membrane rejection performances toward Bovine Serum Albumin (BSA) increased with the BKC composition in both dead-end and cross-flow filtration processes. The chitosan/BKC/PEG/CNT nanocomposite membranes have great potential in wastewater treatments for minimizing biofouling without reducing the water purification performance.

19.
ACS Appl Mater Interfaces ; 14(5): 6740-6753, 2022 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-35080844

RESUMEN

The catalytic activity and stability of metal nanocatalysts toward agglomeration and detachment during their preparation on a support surface are major challenges in practical applications. Herein, we report a novel, one-step, synchronized electro-oxidation-reduction "bottom-up" approach for the preparation of small and highly stable Cu nanoparticles (NPs) supported on a porous inorganic (TiO2@SiO2) coating with significant catalytic activity and stability. This unique embedded structure restrains the sintering of CuNPs on a porous TiO2@SiO2 surface at a high temperature and exhibits a high reduction ratio (100% in 60 s) and no decay in activity even after 30 cycles (>98% conversion in 3 min). This occurs in a model reaction of 4-nitrophenol (4-NP) hydrogenation, far exceeding the performance of most common catalysts observed to date. More importantly, nitroarene, ketone/aldehydes, and organic dyes were reduced to the corresponding compounds with 100% conversion. Density functional theory (DFT) calculations of experimental model systems with six Cu, two Fe, and four Ag clusters anchored on the TiO2 surface were conducted to verify the experimental observations. The experimental results and DFT calculations revealed that CuNPs not only favor the adsorption on the TiO2 surface over those of Fe and AgNPs but also boost the adsorption energy and activity of 4-NP. This strategy has also been extended to the preparation of other single-atom catalysts (e.g., FeNPs-TiO2@SiO2 and AgNPs-TiO2@SiO2), which exhibit excellent catalytic performance.

20.
Front Psychol ; 13: 937905, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36710754

RESUMEN

Reverse correlation (RC) method has been recently used to visualize mental representations of self. Previous studies have mainly examined the relationship between psychological aspects measured by self-reports and classification images of self (self-CIs), which are visual proxies of self-image generated through the RC method. In Experiment 1 (N = 118), to extend the validity of self-CIs, we employed social evaluation on top of self-reports as criterion variables and examined the relationship between self-CIs and social evaluation provided by clinical psychologists. Experiment 1 revealed that the valence ratings of self-CIs evaluated by independent raters predicted social evaluation after controlling for the effects of self-reported self-esteem and extraversion. Furthermore, in Experiment 2 (N = 127), we examined whether a computational scoring method - a method to assess self-CIs without employing independent raters - could be applied to evaluate the valence of participants' self-CIs. Experiment 2 found that the computational scores of self-CIs were comparable to independent valence ratings of self-CIs. We provide evidence that self-CIs can add independent information to self-reports in predicting social evaluation. We also suggest that the computational scoring method can complement the independent rating process of self-CIs. Overall, our findings reveal that self-CIs are a valid and useful tool to examine self-image more profoundly.

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